Signal conditioner apparatus for compensating an electronic material gaging signal

ABSTRACT

Signal conditioner apparatus multiplies electronic material gaging signal by one or more predetermined variable scaling factors to compensate for variations in other material properties which affect the gaged property. For example, material thickness gaging signal variations caused by material temperature variations are compensated for by simultaneously feeding the thickness signals through two adjustable-gain amplifiers preset at separate values which establish an adjustable range of temperature compensation. Amplifier outputs are proportioned in response to a material temperature measurement made during material gaging, thereby providing a single temperature compensated material thickness signal at an output. Material composition compensation is provided in combination with temperature compensation by first feeding the thickness signal through a single presettable-gain amplifier. All amplifier gains are preset or controlled from a data source which correlates compensation requirements with temperature and composition effects on material thickness gaging.

United States Patent [1 1 Mangan et al.

[111 3,832,549 [451 Aug. 27, 1974 i 1 SIGNAL CONDITIONER APPARATUS FOR COMPENSATING AN ELECTRONIC MATERIAL GAGING SIGNAL [75] Inventors: Edmund L. Mangan, Bethlehem;

William G. Bartlett, Stockertown, both of Pa.

[73] Assignee: Bethlehem Steel Corporation,

Bethlehem, Pa.

[22] Filed: June 22, 1972 [21] Appl. N0.: 265,110

[52] U.S. Cl. 250/358, 250/252 [51] Int. Cl. G0ln 23/00 [58] Field of Search 250/83 C, 83.3 D, 252 250/358, 359, 360

[56] References Cited UNITED STATES PATENTS 3,4!7244 l2/l968 Kramer 250/833 D 3.5 l3.3l() 5/1970 Chopc et al. 250/833 D Primary Eraminer-Archie R. Borchelt Attorney, Agent. or FirmJoseph J. OKeefe; John I. Iverson; George G. Dower 57] ABSTRACT Signal conditioner apparatus multiplies electronic material gaging signal by one or more predetermined variable scaling factors to compensate for variations in other material properties which affect the gaged property. For example, material thickness gaging signal variations caused by material temperature variations are compensated for by simultaneously feeding the thickness signals through two adjustable-gain amplifiers preset at separate values which establish an adjustable range of temperature compensation. Amplifier outputs are proportioned in response to a material temperature measurement made during material gaging, thereby providing a single temperature compensated material thickness signal at an output. Material composition compensation is provided in combination with temperature compensation by first feeding the thickness signal through a single presettable-gain amplifier. All amplifier gains are preset or controlled from a data source which correlates compensation requirements with temperature and composition effects on material thickness gaging.

20 Claims, 5 Drawing Figures TEMPERATURE INDICATOR UTILIZATION DEVICE CONDITIONER m P 8 R. ER m wm WE Q MM 5 R E 3 2W m m 5 WW/,/ 3 M rm 9 El 3 E MM H T 7. P EC m W 8 w T m 2 o I m m w MW 5.. .Q Do m..u mno zo .5wmmou 2 RR El 0 I A S .m m:o twzua m 3 A Rm A Hm Mm E 2 M 5 R l U0 MM mm D MN I E m 1 .W F I PATENIEmuczmu RADIATION DETECTOR SIGNAL CONDITIONER APPARATUS FOR COMPENSATING AN ELECTRONIC MATERIAL GAGING SIGNAL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates broadly to improvements in material gaging apparatus. More particularly, the invention relates to electronic signal conditioning apparatus for compensating a material property gaging signal for variations from the actual property due to variations in other material properties which affect the gaged property. The invention will be described herein with reference to a hot steel rolling mill where steel strip or plate thickness signals obtained by a radiation type gage are compensated for variations in steel composition and temperature of the character and magnitude normally experienced in such operations. However, the invention is equally applicable in a variety of other industrial and laboratory installations, as well as to gaging properties of other materials and other material properties such as weight-per-unit area and density.

2. Description of the Prior Art Thickness gaging in contemporary hot steel strip or plate mills, which must be corrected to standard conditions, is done when the strip or plate is moving, while material thickness may be in a range of up to three inches and more, material temperature in a range of between about l,lOO and 2,200 F. and subject to variation during rolling, and material density, or composition or grade as it is frequently referred to, may be in a range of i percent of calibration standards. However, density is considered constant for a given run through the rolling mill. X-ray gages are generally used for thickness deviation measurements in steel rolling mills and these gages operate on the mass absorption phenomenon. That is, when steel strip is caused to enter a beam of penetrative radiation and its thickness varies linearly, the amount of radiation absorbed by the steel per-unit-area thereof is registered exponentially on a radiation-sensitive detector.

It is to be noted that radiation absorption, and therefore apparent material thickness, also varies (1) randomly because of the statistical manner in which X- radiation emenates from its source, (2) as a complex function of radiation wavelength and intensity, (3) as a complex function of material composition or density, and (4) as a predetermined function of material temperature because as material is heated its thickness and volume, and hence its density, changes. The temperature function is considered linear within certain limits for a given material composition within a given temperature range and cooling at a constant predetermined rate. Under other conditions, the temperature function is considered nonlinear. Thus. it will become apparent that variations in material composition and/or temperature (along with other parameters) from standard conditions will cause errors, either high or low, in material thickness signals obtained by radiation type gages.

The effects of material composition and temperature variations with respect to steel thickness measurements by X-radiation methods are exemplified in US. Pat. No. 3,482,098 to E. L. Mangan. The Mangan teachings while quite satisfactory are directed only to a thickness deviation gage, rather than to a direct-reading gage,

and to the generation of a thickness compensation voltage which is scaled and later algebraically summed with a thickness deviation voltage; Such teachings are somewhat limited with respect to flexibility of compensation.

SUMMARY OF THE INVENTION One of the objects of this invention is to provide improved electronic signal conditioner apparatus for compensating a material property gaging signal for variations from the actual property due to variations in at least one other material property which affect the gaged property.

Another object of this invention is to provide said electronic signal conditioner apparatus for compensating a direct-reading gaging signal.

Still another object of this invention is to provide said electronic signal conditioner apparatus for compensating a direct-reading gaging signal by operating directly on said signal as opposed to generating a separate compensation signal for later combination with a gaging deviation signal.

A further object of this invention is to provide said electronic signal conditioner apparatus for compensating a material-thickness gaging signal for variations in material composition and/or temperature, including temperature variations during thickness gaging.

Another object of this invention is to provide said electronic signal conditioner apparatus with improved flexibility of compensating a material gaging signal.

The foregoing objects can be attained by electronic signal conditioner apparatus which directly multiplies a direct-reading material thickness signal, for example, by one or more predetermined variable scaling factors for effecting said compensation of the thickness signal. Material temperature compensation is developed by simultaneously feeding the material thickness signal through two adjustable-gain amplifiers preset at separate values which establish an adjustable range of temperature compensation. Amplifier outputs are proportioned in response to material temperature measurements made during material gaging, thereby providing a single temperature compensated material thickness signal at an output. Material composition compensation, which should remain constant during gaging, is provided in combination with temperature compensation by first feeding the thickness signal through a single presettable-gain amplifier. All amplifier gains are preset or controlled from a data source which correlates compensation requirements with temperature and composition effects on material thickness gaging.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a radiation gaging system which incorporates the signal conditioner apparatus of this invention.

FIG. 2 is a schematic diagram of one form of material temperature compensator of the present invention.

FIG. 3 is a graph illustrating (A) one of a family of curves on the effects of steel plate density versus temperature, and (B) the straight-line percent correction applied to the steel thickness signal by a material temperature compensator of the present invention.

FIG. 4 is a schematic diagram of a modification of the embodiment shown in FIG. 3.

FIG. 5 is a schematic diagram of a combined material composition and temperature compensator of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a typical radiation gaging system is shown wherein a well known radiation source directs a beam of penetrative radiation 1 1 through a steel product in a hot steel rolling mill, which product will be referred to as plate P for illustrative purposes, although the steel product could be a strip instead of a plate. While passing through plate P, radiation beam 11 is subject to attenuation which varies according to the well known nonlinear mass absorption phenomenon described in the Mangan patent, supra. Subsequently, this beam of radiation becomes known as a beam of emergent radiation 12 which is imaged upon radiation detector 13.

Radiation detector 13 converts emergent radiation 12 into an electrical signal which is applied to measuring circuits 14, the latter including the necessary circuitry to produce an electronic thickness signal which varies substantially linearly from zero to full scale proportional to the thickness of plate P. For convenience, the linear thickness signal may be scaled to engineering units, i.e., 3.000 volts for 3.000 inches thickness of plate P. I

As described more fully below, the linear thickness voltage is fed to signal conditioner apparatus 15 of the present invention. Signal conditioner apparatus 15 consists essentially of signal conditioner 16, which includes temperature and composition compensators with adjustable-gain amplifiers; data source 17 for enabling the presetting of amplifier gains so as to multiply the thickness voltage by appropriate scaling factors; and temperature indicator 18 which measures plate P temperature by means of a signal transmitted thereto by pyrometer 19, or other temperature responsive device. Temperature indicator l8 feeds a temperature signal to the temperature compensator in signal conditioner l6, and to data source 17, as will be explained more fully below. As a result of multiplying the thickness-voltage in signal conditioner 16, the compensated thickness voltage produced at its output is now corrected to standard conditions. That is, the compensated thickness voltage is an instantaneous representation of what plate P thickness will be when later cooled to room temperature, as well as accounting for changes in plate P density from radiation gaging standards, thereby overcoming the errors in emergent beam of radiation 12 caused by variations in temperature and composition of plate P.

The compensated thickness voltage produced at the output of signal conditioner 16 in signal conditioner apparatus 15 is fed to utilization device 20 such as an indicator, recorder or computer.

Still referring to FIG. .1, thickness signal conditioner 16 having composition and temperature compensation features for accommodating complex corrective functions will be described more fully. Ordinarily in laboratory types of radiation thickness gages, the composition, or density, of steel plate P is considered constant as is plate temperature. However, in hot steel plate rolling mills, plate composition is considered constant only for a given plate because throughout daily production runs the plate-to-plate variation in composition, or density, from calibration standards may require as much as plus or minus 10 percent correction of the plate thickness voltage. Similarly, in mill practice plate P temperature is considerably above the 70 F. gage calibration standard temperature and more particularly, in a range of about l,l00 F. to about 2,200 F. In addition, plate P temperature varies during rolling and gaging due to varying plate cooling effects. Plate cooling effects are governed by plate composition, temperature and cooling rate, and ambient environmental conditions, and these effects may differ from plate-to-plate. As will be explained more fully below, variations in plate P temperature cause variations in both the plates physical and metallurgical properties and these variations also cause plate P density to vary, thus causing a variation in the amount of radiation from beam 11 absorbed by plate P. In practice, plate P temperature variations may require up to about 10 percent additional correction of the plate thickness voltage.

Referring now to FIG. 2, one embodiment of the FIG. 1 signal conditioner 16 includes only temperature compensator 21 for modifying the thickness voltage from measuring circuits 14 for variations therein caused by variations in temperature of plate P. As noted above, the amount of radiation absorbed by'steel plate P is a function of the mass of steel plate P in radiation beam 11. When plate P is at a temperature elevated above room temperature it expands volumetrically, i.e., in three dimensions, thereby causing a portion of the mass which has expanded in the plane perpendicular to radiation beam 11 to leave the beam and not be available for energy absorption. This effect of changing mass results in plate P appearing thinner to radiation beam 11 than when at room temperature, thus requiring a positive correction to be made in the thickness voltage. Referring to the equation on mass absorption phenomenon in the Mangan patent, supra, it will be observed that variations in plate mass herein, which are occasioned by variations in plate P temperature, also cause variations in plate density and mass absorption coefficient which also require a complex corrective function.

Stated somewhat simply, percent temperature correction as a function of plate P temperature is expressed as follows:

Percent temperature correction 2 Ta where:-

T plate P temperature in degrees F. a ==coefficient of linear expansion for plate P at temperature T. Density of steel plate P varies as a predetermined function of plate chemical composition, plate temperature and rate of cooling. It is well known that steel is a crystalline structure and that the behavior of such structures changes at elevated temperatures. Further,

that the degree of change and temperature at which When interpreting FIG. 3, curve A, a sharp reversal in curvature occurring at point C will be noted. This reversal occurs at what is known as the transformation temperature of steel plate P. That is, the temperature at which a change in phase occurs in the steel alloy structure, for example, when austenite which formed during heating changes to ferrite upon cooling or to ferrite plus cementite when cooling is completed. There are transformation temperature ranges, that is, ranges of temperatures at which austenite forms during heating and transforms into ferrite, etc. during cooling. The heating and cooling temperature ranges are distinct, sometimes overlap but never coincide, and the cooling ranges are lower than the heating ranges. The limiting temperatures of each range depend on the composition of the steel alloy and on the rate of change of temperature, particularly during cooling. In addition, when accommodating a wide range of steel alloys, the transformation temperature range varies in span and location along the temperature axis in FIG. 3, curve A; the location of the transformation temperature, i.e., point C, varies along the temperature axis and sometimes occurs at a temperature of less than 1, 1 00 F the starting point and initial slope of curve A at l,l0O F., as well as the vertical separation at point C and the final slope of Curve A, all vary in magnitude with chemical composition and cooling rate of steel plate P.

All of the foregoing variable factors establish the metallurgical properties of steel plate P which affect its density. Variations in metallurgical properties, together with the above-noted variations in the physical property of steel plate P due to mass redistribution from volumetric expansion, make up the total variations in density over a given temperature range and are operative in determining a particular value of coefficient (a) in equation (1) for a given plate P. Thus, it will become apparent that to accommodate a variety of steel alloys, and other materials, the specific percentage correction applied by temperature compensator 21 to the thickness voltage from measuring circuits 14 must be determined from a data source covering a number of physical and chemical properties of a variety of materials to be gaged. Also, temperature compensation must be applied over a given range, such as between a low limit of about l,l0O F. and a high limit of about 2,200 F. as experienced in a hot steel plate rolling mill.

Provisions are made in temperature compensator 21 for a high degree of flexibility in establishing the inde pendent selection of either positive or negative percent temperature compensation applied at the low and high temperature limits, as well as in establishing the starting and ending percentages of correction at said temperature limits, thereby enabling the establishment of any rate, or rate change, of temperature compensation required within predetermined percentage correction limits. Provisions are also made for proportioning the percentage temperature compensation established between temperature limits according to an actual temperature measurement of plate P at any time during gaging.

The correction function of temperature compensator 21 is accomplished by feeding the thickness voltage from measuring circuits 14 to input terminal 22, then through dual multiplying circuitry by passing it through summing resistors 23 and 24 and into low-and-highlimit scaling amplifiers 25 and 26, respectively, said amplifiers being of the operational summing type. Ad-

justable feedback circuits connected across scaling amplifiers 25 and 26 are provided by way of fixed resistors 27 and 28 and linear potentiometers 29 and 30 serially connected with resistors 27 and 28, respectively. For unity gain of amplifiers 25 and 26, resistors 23 and 27 should be of equal resistance value as should be resistors 24 and 28, and preferably all four resistors should be equal. In one arrangement, linear potentiometers 29 and 30 may each be a lO-turn precision analog device and sliders 31 and 32 each provided with a calibrated dial. In another arrangement, potentiometers 29 and 30 may each be digital devices having thumb-wheel selectors operated under control of a gaging operator. Or alternatively, digital potentiometers 29 and 30 may be relay controlled in response to action of a computer described below. Linear potentiometer sliders 31 and 32 establish low-limit and high-limit gain values of amplifiers 25 and 26, respectively, and are set according to provisions of data source 17 as will be explained below, whereby the thickness voltage from measuring circuits 14 is multiplied by positive or negative percentage correction factors selected according to equation (1).

When properties of the material being gaged require a positive maximum of say 10 percent temperature correction, the resistance value of potentiometers 29 and 30 should be 0.1 that of resistors 27 and 28, respectively. By adjusting low-limit and high-limit potentiometer sliders 31 and 32, the gain of scaling amplifiers 25 and 26, respectively, is set above unity at, for example, 2 percent and 4 percent temperature correction, respectively. This type of correction is illustrated graphically in FIG. 3, curve B, where the best-fit straight line temperature correction is applied to the thickness voltage as required for the density versus temperature properties of the particular steel plate P illustrated in FIG. 3, curve A. Other steel alloys, as well as other materials, may require different settings of potentiometer sliders 31 and 32.

When properties of the material being gaged require a positive temperature correction factor having a negative rate of change between low-and-high temperature limits, then potentiometer slider 31 and 32 settings may be reversed to say 4 percent and 2 percent, respectively.

Further, when properties of the material being gaged require a negative maximum of say 10 percent temperature correction, then the resistance values of resistors 27 and 28 are only 0.9 of resistors 23 and 24. This arrangement permits the gain of scaling amplifiers 25 and 26 to be adjusted between unity and 0.9 to establish a negative percent temperature correction at either the low or the high-limit of temperature correction. The inverse of FIG. 3, curve B would illustrate this type of correction. In addition, a reverse slope of curve B can be obtained by adjusting the percentage relationship of potentiometer sliders 31 and 32 as noted above.

Regardless of what the feedback circuit parameters are, the outputs of low-limit and high-limit scaling amplifiers 25 and 26 are fed to opposite ends of precision linear potentiometer 33. Potentiometer slider 34 is driven by a conventional servo type of temperature indicator 18, the latter being responsive to and calibrated for pyrometer 19, or other temperature sensing device. Pyrometer 19 senses the temperature and temperature changes of steel plate P during gaging operations and sends a corresponding signal to temperature indicator 18. As potentiometer slider 34 is moved from lowto high-limit position it proportions the outputs of lowand high-limit scaling amplifiers 25 and 26, respectively. This provides the proper percent and rate of temperature compensation of the thickness voltage at output terminal 35 of temperature compensator 21.

Where the nature of the steel plate P composition is such as to have a different nonlinearity than that exemplified in FIG. 3, curve A, then potentiometer 33 may be fabricated to accommodate such nonlinearity. Hence, the percentage correction between lowand high-limits of amplifiers 25 and 26 would not follow a best fit straight line as in FIG. 3, curve B, but would be correspondingly nonlinear and extend the useful range of temperature compensation provided by signal conditioner 21.

Data source 17 is provided to determine the position of, and if desired to actuate, the percentage settings of potentiometer sliders 31 and 32, or their equivalent, for compensating the thickness voltage the correct temperature percentages as determined from equation (1). Prior to gaging, the percentage, and polarity if necessary, of temperature correction data is pre-calculated and tabularized for each different type of plate P composition, density versus temperature and cooling rate expected to be encountered during gaging. When using either the analog form or the thumb-wheel digital form of potentiometers 29 and 30 in temperature compensator 21, the tabular correction data may be in chart form suitable for a gage operator to read and cause manipu lation of potentiometer sliders 31 and 32 to lowand high-percentage correction positions corresponding to known properties of plate P. When using the digital relay form of potentiometers 29 and 30, the relays may be controlled in response to tabular data stored in a computer incorporated, but not shown, in data source 17.

In some hot steel plate rolling mills the composition and cooling rate variations in plate P may be sufficiently small that such effects on temperature correction of the thickness signal are tolerable within prescribed gaging system accuracy limits. This will permit pre-setting of potentiometer sliders 31 and 32 initially and making necessary adjustments thereto only at the time of gage calibration. In other installations, the cooling rate of plate P may change after initial settings of potentiometer sliders 31 and 32 so that during gaging of a particular plate P, a change in position of either or both sliders will be required to maintain the proper amount temperature correction of the thickness signal. For this reason a temperature signal is fed from temperature indicator 18 to data source 17. Here plate temperature and rate of temperature change may be indicated to a gage operator so that appropriate changes may be made in the positions of potentiometer slider 31 and/or 32 in order to produce the proper temperature compensation of the thickness signal. Alternatively, the temperature signal may be fed to the unidentified computer in data source 17 to determine plate temperature and rate of temperature change in order to effect the necessary changes in temperature compensation of the thickness signal.

Turning to FIG. 4, another embodiment of the FIG. 1 signal conditioner 16 includes only temperature compensator 21a for modifying the thickness voltage from measuring circuits 14 for variations therein caused by variations in temperature of plate P. Temperature compensator 21a is a modification of temperature compensator 21 embodiment shown and described in connection with FIG. 2 and, with one exception, is identical to the latter in identification and description.

In temperature compensator 21a, the high-limit feedback circuit around scaling amplifier 26 includes an additional gain adjusting potentiometer 290 which is identical to low-limit gain adjusting potentiometer 29. Slider 31a is coupled to slider 31 so as to be preset in unison therewith by data source 17. This arrangement will automatically limit percent temperature correction, FIG. 3, curve B, to that amount where the highlimit scaling of the thickness signal is equal to or greater than the low-limit scaling thereof. In other words, the percent temperature correction of low-limit scaling adjustment will always be added to the percent temperature correction of the high-limit, thus simplifying scaling adjustments where a variable low-limit is desired while maintaining the same rate of temperature correction of the thickness voltage.

Still another embodiment of the FIG. 1 signal conditioner 16 is shown in FIG. 5 wherein composition and temperature compensator 36 includes composition compensator 37 combined with the temperature compensator 21 shown in FIG. 2 for modifying the thickness voltage from measuring circuits 14 for variations therein caused by variations of both composition and temperature of plate P.

Thickness signal conditioner 36 receives the thickness voltage at input terminal 22 and feeds it into composition compensator 37 where the thickness voltage is modified for variations therein caused by variations in composition of plate P. Variations in composition of plate P cause variations in plate density and, as will be observed in the equation on the mass absorption phenomenon in the Mangan patent, supra; variations in density also affect the mass absorption coefficient, whereby the combined effects of such variations require a complex corrective function. However, also stated somewhat simply, the percent correction of the thickness voltage as a function of plate P composition is expressed as follows:

Percent Composition Correction =i pk wheiza p density, or composition, of plate P k composition coefficient of plate P, either a plus or minus value when referenced to a composition calibration standard. Composition coefficient (k of steel plate P varies as a predetermined function of plate density and density effects on the mass absorption coefficient. Thus, a percentage composition correction of the thickness voltage at input terminal 22 must be selected accordingly.

Percentage composition correction of the thickness voltage is accomplished by feeding the thickness voltage through summing resistor 38 and into scaling amplifier 39 of the operational summing type where, by means of an adjustable feedback network 40, the thickness voltage is multiplied by a positive or negative percentage correction factor selected according to equation (2). Adjustable feedback network 40 consists of resistor 41, potentiometer 42 and resistor 43 seriesconnected across amplifier 39, and a SPDT polarity selector switch 44 having negative and positive poles also connected across amplifier 39, the common pole of switch 44 being connected to potentiometer slider 45. In one arrangement potentiometer 42 may be a lO-turn precision analog device and slider 45 provided with a calibrated dial. In another arrangement, potentiometer 42 may be a digital device having thumb-wheel selectors operated under control of a gaging operator as is switch 44. Or alternatively, both digital potentiometer 42 and polarity selector switch 44 may be relay controlled in response to computer action by modifying the computer noted above in connection with data source 17. Potentiometer 42 may be fabricated with either linear or nonlinear characteristics similar to potentiometers 29 and 30 for matching either straight line or nonlinear correction requirements.

A composition compensation range of plus or minus 10 percent is established by limiting the resistance value of potentiometer 42 and resistor 43 to 0.1 and 0.9

- that of resistor 41, respectively. Thus, when setting potentiometer slider 45 at percent correction and turning polarity selector switch from to positions, the gain of amplifier 39 will remain at unity and the thickness voltage will not be multiplied by any percentage factor. However, when setting potentiometer slider 45 at any value up to percent, and turning selector switch 44 to either a or position, then the gain of amplifier 39 will be set up to 1.1 or down to 0.9, respectively. thus multiplying the thickness voltage by up to plus or minus 10 percent, respectively. The output of amplifier 39 provides the output for composition compensator 37 and this output is fed to temperature compensator 21 by way of input resistors 23 and 24. Temperature compensator 21 operates to further modify the composition compensated thickness voltage and produce a combined composition and temperature compensated thickness voltage at output terminal 35.

Data source 17 is also provided to determine the position of, and if desired to actuate, composition polarity selector switch 44 and the percentage setting of potentiometer slider 45, or its equivalent, for compensating the thickness voltage the correct composition percentage as determined from equation (2). Prior to gaging, the percentage and polarity of composition correction data is pre-calculated and tabularized for each different type of plate P composition expected to be gaged. When using either the analog form or the thumb-wheel digital form of potentiometer 42 in composition compensator 37, the tabular correction data may be in chart form suitable for a gage operator to read and cause manipulation of switch 44 and potentiometer slider 45 to required percentage correction positions corresponding to a known composition of plate P. When using the digital relay form of potentiometer 42, the relays may be controlled in response to tabular data stored in the computer incorporated, but not shown, in data source 17.

In an alternative arrangement of the present invention, the temperature compensator 21 shown in FIG. 2 may have the value of its feedback circuit resistor modified so that the multiplying factors of amplifiers 25 and 26 may, in a single presetting of potentiometer sliders 31 and 32 by data source 17, provide the total percent composition and temperature compensation of plate P thickness signal. This may be accomplished. for example, by a computer solution to equations (l) plus (2) in data source 17. In yet another alternative arrange- 6 around amplifiers 25 and 26 in the embodiment of FIG.

2 and presetting these as described above, whereby compensator 21 will produce a combined composition and temperature compensated thickness voltage.

We claim:

1. A signal conditioner for compensating an elecv tronic material gaging signal for variations due to variations in a materialsecond property, said material second property represented by a second signal source, said signal conditioner comprising:

a. first input means for receiving said electronic material gaging signal,

b. second input means for receiving a material second property signal,

0. first and second scaling amplifiers each receiving said electronic gaging signal and each having gainadjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic gaging signal multiplication desired at two predetermined values of said material second property,

(1. circuit means for proportioning said first and second amplifier output signals in response to said second property signal to produce a single compensated electronic gaging signal, and

e. output circuit means for issuing said compensated electronic gaging signal.

2. The signal conditioner of claim 1 wherein said gain-adjusting means for at least one of said scaling amplifiers is adapted to be preset to produce at least one scaling factor in a range from greater-to-less than unity.

3. The signal conditioner of claim 1 wherein the two predetemiined values of said second property signal are lower and upper limits thereof.

4. The signal conditioner of claim 3 wherein the lower and upper limits of said second property signal are zero and full scale values thereof.

5. The signal conditioner of claim 1 wherein said second scaling amplifier gain-adjusting means is circuited to include an adjustable element adjusted simultaneously with said first scaling amplifier gain-adjusting means so as to modify said second scaling factor by a predetemiined amount of said first scaling factor.

6. The signal conditioner of claim 5 wherein said second scaling amplifier gain-adjusting means circuitry is 7 adapted to add to the second scaling factor an amount substantially equal to the first scaling factor.

7. In a material thickness gaging system, a signal conditioner for compensating an electronic material thickness signal for variations due to variations in material temperature, said material temperature represented by a temperature signal source, said signal conditioner comprising:

a. first input means for receiving said electronic material thickness signal,

b. second input means for receiving a material temperature signal,

c. first and second scaling amplifiers each receiving said electronic material thickness signal and having gain-adjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic thickness signal multiplication desired at lower and upper values of said material temperature signal,

d. circuit means for proportioning the first and second amplifier output signals in response to said material temperature signal to produce a single temperature compensated material thickness signal,

and

e. output means for issuing said temperature compensated material thickness signal.

8. Signal conditioner apparatus for compensating an electronic material gaging signal for variations due to variations in a material second property, said apparatus comprising:

a. a material second property signal source,

b. a signal conditioner comprising:

1. first input means for receiving said electronic material gaging signal,

2. second input means for receiving a material second property signal,

3. first and second scaling amplifiers each receiving said electronic gaging signal and each having gain-adjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic gaging signal multiplication desired at two predetermined values of said material second property,

4. circuit means for proportioning said first and second amplifier output signals in response to said second property signal to produce a single compensated electronic gaging signal, and

c. output circuit means for issuing said compensated electronic gaging signal.

9. Signal conditioner apparatus for-compensating an electronic material gaging signal for variations due to variations in a material second property, said apparatus comprising:

a. a material second property signal source,

b. a signal conditioner comprising:

1. first input means for receiving said electronic material gaging signal,

2. second input means for receiving a material second property signal,

3. first and second scaling amplifiers each receiving said electronic gaging signal and each having gain-adjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic gaging signal multiplication desired at two predetermined values of said material second property,

4. circuit means for proportioning said first and second amplifier output signals in response to said second property signal to produce a single compensated electronic gaging signal,

c. a data source for determining the presetting of the gain-adjusting means for at least one of said first and second scaling amplifiers, and

d. output circuit means for issuing said compensated electronic gaging signal.

10. The apparatus of claim 9 wherein said data source includes computer means for determining the presetting of at least one of said gain adjusting means.

11. The apparatus of claim 9 wherein said data source includes computer means for controlling the setting of at least one of said gain adjusting means.

12. The apparatus of claim 11 wherein said computer means is adapted to calculate a rate of change of said material second property signal and to enable the setting of at least one of said gain adjusting means to be regulated accordingly.

13. A signal conditioner for compensating an electronic material gaging signal for variations due to variations in material second and third properties, said material second and third properties represented by corresponding second and third signal sources, said signal conditioner comprising:

a. first input means for receiving said electronic material gaging signal,

b. second input means for receiving a material second property signal,

0. third input means for receiving a material third property signal, 7

d. a first scaling amplifier receiving said electronic gaging signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of gaging signal multiplication desired at a predetermined value of said material second property,

e. second and third scaling amplifiers each receiving the output of said first scaling amplifier and each having gain adjusting means preset at respective second and third scaling factors, said scaling factors corresponding to the amount of gaging signal multiplication desired at two predetermined values of said material third property,

f. circuit means for proportioning said second and third amplifier output signals in response to said third property signal to produce a single compensated electronic gaging signal, and

g. output circuit means for issuing said compensated electronic gaging signal.

14. The signal conditioner of claim 13 wherein the gain adjusting means of at least one of said scaling amplifiers is adapted to be preset to produce at least one scaling factor in a range from greater-to-less than unity.

15. In a material thickness gaging system, a signal conditioner for compensating an electronic material thickness signal for variations due to variations in material composition and temperature, said material composition and temperature represented by material composition and temperature signal sources, said signal conditioner comprising:

a. first input means for receiving said electronic material thickness signal,

b. second input means for receiving said material composition signal,

c. third input means for receiving said material temperature signal,

(1. a first scaling amplifier receiving said electronic thickness signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of thickness signal multiplication desired at a predetermined value of material composition,

e. second and third scaling amplifiers each receiving said material composition-compensated thickness signal and each having gain-adjusting means preset at respective second and third scaling factors, said scaling factors corresponding to the amount of material composition-compensated thickness signal multiplication desired at lower and upper values of said material temperature,

f. circuit means for proportioning the first and second amplifier output signals in response to said material temperature signal to produce a single composition and temperature compensated material thickness signal, and

gr output means for issuing said composition and temperature compensated material thickness signal.

16. Signal conditioner apparatus for compensating an electronic material gaging signal for variations due to variations in material second and third properties, said apparatus comprising:

a. a material second property signal source,

b. a material third property signal source,

c. a signal conditioner comprising:

1. first input means for receiving said electronic material gaging signal,

2. second input means for receiving a material second property signal,

3. third input means for receiving a material third property signal,

4. a first scaling amplifier receiving said electronic gaging signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of gaging signal multiplication desired at a predetermined value of said material second property,

5. second and third scaling amplifiers each receiving the output of said first scaling amplifier and each having gain adjusting means preset at respective second and third scaling factors, said scaling factors corresponding to the amount of gaging signal mulitplication desired at two predetermined values of said material third property,

6. circuit means for proportioning said second and third amplifier output signals in response to said third property signal to produce a single compensated electronic gaging signal, and

d. output circuit means for issuing said compensated electronic gaging signal.

17. Signal conditioner apparatus for compensating an electronic material gaging signal for variations due to variations in material second and third properties, said apparatus comprising:

a. a material third property signal source,

b. a signal conditioner comprising:

1. first input means for receiving said electronic 14 material gaging signal,

2. second input means for receiving a material second property signal,

3. third input means for receiving a material third property signal,

4. a first scaling amplifier receiving said electronic gaging signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of gaging signal multiplication desired at a predetermined value of said material second property,

5. second and third scaling amplifiers each receiving the output of said first scaling amplifier and each having gain adjusting means preset at respective second and third scaling factors, said scaling factors corresponding to the amount of gaging signal multiplication desired at two predetermined values of said material third property,

6. circuit means for proportioning said second and third amplifier output signals in response to said third'property signal to produce a single compensated electronic gaging signal,

c. a data source for providing a material second property signal and for determining the presetting of the gain adjusting means for at least one of said first, second and third scaling amplifiers, and

d. output circuit means for issuing said compensated electronic gaging signal.

18. The apparatus of claim 17 wherein said data source includes computer means for determining the presetting of at least one of said gain adjusting means.

19. The apparatus of claim 17 wherein said data source includes computer means for controlling the setting of at least one of said gain adjusting means.

20. The apparatus of claim 19 wherein said computer means is adapted to calculate a rate of change of said material third property signal and to enable the setting of at least one of said gain adjusting means to be regulated accordingly. 

1. A signal conditioner for compensating an electronic material gaging signal for variations due to variations in a material second property, said material second property represented by a second signal source, said signal conditioner comprising: a. first input means for receiving said electronic material gaging signal, b. second input means for receiving a material second property signal, c. first and second scaling amplifiers each receiving said electronic gaging signal and each having gain-adjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic gaging signal multiplication desired at two predetermined values of said material second property, d. circuit means for proportioning said first and second amplifier output signals in response to said second property signal to produce a single compensated electronic gaging signal, and e. output circuit means for issuing said compensated electronic gaging signal.
 2. The signal conditioner of claim 1 wherein said gain-adjusting means for at least one of said scaling amplifiers is adapted to be preset to produce at least one scaling factor in a range from greater-to-less than unity.
 2. second input means for receiving a material second property signal,
 2. second input means for receiving a material second property signal,
 2. second input means for receiving a material second property signal,
 2. second iNput means for receiving a material second property signal,
 3. first and second scaling amplifiers each receiving said electronic gaging signal and each having gain-adjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic gaging signal multiplication desired at two predetermined values of said material second property,
 3. first and second scaling amplifiers each receiving said electronic gaging signal and each having gain-adjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic gaging signal multiplication desired at two predetermined values of said material second property,
 3. third input means for receiving a material third property signal,
 3. The signal conditioner of claim 1 wherein the two predetermined values of said second property signal are lower and upper limits thereof.
 3. third input means for receiving a material third property signal,
 4. a first scaling amplifier receiving said electronic gaging signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of gaging signal multiplication desired at a predetermined value of said material second property,
 4. The signal conditioner of claim 3 wherein the lower and upper limits of said second property signal are zero and full scale values thereof.
 4. circuit means for proportioning said first and second amplifier output signals in response to said second property signal to produce a single compensated electronic gaging signal, c. a data source for determining the presetting of the gain-adjusting means for at least one of said first and second scaling amplifiers, and d. output circuit means for issuing said compensated electronic gaging signal.
 4. circuit means for proportioning said first and second amplifier output signals in response to said second property signal to produce a single compensated electronic gaging signal, and c. output circuit means for issuing said compensated electronic gaging signal.
 4. a first scaling amplifier receiving said electronic gaging signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of gaging signal multiplication desired at a predetermined value of said material second property,
 5. second and third scaling amplifiers each receiving the output of said first scaling amplifier and each having gain adjusting means preset at respective second and third scaling factors, said scaling factors corresponding to the amount of gaging signal mulitplication desired at two predetermined values of said material third property,
 5. The signal conditioner of claim 1 wherein said second scaling amplifier gain-adjusting means is circuited to include an adjustable element adjusted simultaneously with said first scaling amplifier gain-adjusting means so as to modify said second scaling factor by a predetermined amount of said first scaling factor.
 5. second and third scaling amplifiers each receiving the output of said first scaling amplifier and each having gain adjusting means preset at respective second and third scaling factors, said scaling factors corresponding to the amount of gaging signal multiplication desired at two predetermined values of said material third property,
 6. The signal conditioner of claim 5 wherein said second scaling amplifier gain-adjusting means circuitry is adapted to add to the second scaling factor an amount substantially equal to the first scaling factor.
 6. circuit means for proportioning said second and third amplifier output signals in response to said third property signal to produce a single compensated electronic gaging signal, c. a data source for providing a material second property signal and for determining the presetting of the gain adjusting means for at least one of said first, second and third scaling amplifiers, and d. output circuit means for issuing said compensated electronic gaging signal.
 6. circuit means for proportioning said second and third amplifier output signals in response to said third property signal to produce a single compensated electronic gaging signal, and d. output circuit means for issuing said compensated electronic gaging signal.
 7. In a material thickness gaging system, a signal conditioner for compensating an electronic material thickness signal for variations due to variations in material temperature, said material temperature represented by a temperature signal source, said signal conditioner comprising: a. first input means for receiving said electronic material thickness signal, b. second input means for receiving a material temperature signal, c. first and second scaling amplifiers each receiving said electronic material thickness signal and having gain-adjusting means preset at respective first and second scaling factors, said scaling factors corresponding to the amount of electronic thickness signal multiplication desired at lower and upper values of said material temperature signal, d. circuit means for proportioning the first and second amplifier output signals in response to Said material temperature signal to produce a single temperature compensated material thickness signal, and e. output means for issuing said temperature compensated material thickness signal.
 8. Signal conditioner apparatus for compensating an electronic material gaging signal for variations due to variations in a material second property, said apparatus comprising: a. a material second property signal source, b. a signal conditioner comprising:
 9. Signal conditioner apparatus for compensating an electronic material gaging signal for variations due to variations in a material second property, said apparatus comprising: a. a material second property signal source, b. a signal conditioner comprising:
 10. The apparatus of claim 9 wherein said data source includes computer means for determining the presetting of at least one of said gain adjusting means.
 11. The apparatus of claim 9 wherein said data source includes computer means for controlling the setting of at least one of said gain adjusting means.
 12. The apparatus of claim 11 wherein said computer means is adapted to calculate a rate of change of said material second property signal and to enable the setting of at least one of said gain adjusting means to be regulated accordingly.
 13. A signal conditioner for compensating an electronic material gaging signal for variations due to variations in material second and third properties, said material second and third properties represented by corresponding second and third signal sources, said signal conditioner comprising: a. first input means for receiving said electronic material gaging signal, b. second input means for receiving a material second property signal, c. third input means for receiving a material third property signal, d. a first scaling amplifier receiving said electronic gaging signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of gaging signal multiplication desired at a predetermined value of said material second property, e. second and third scaling amplifiers each receiving the output of said first scaling amplifier and each having gain adjusting means preset at respective second and third scaling factors, said scaling factors correspOnding to the amount of gaging signal multiplication desired at two predetermined values of said material third property, f. circuit means for proportioning said second and third amplifier output signals in response to said third property signal to produce a single compensated electronic gaging signal, and g. output circuit means for issuing said compensated electronic gaging signal.
 14. The signal conditioner of claim 13 wherein the gain adjusting means of at least one of said scaling amplifiers is adapted to be preset to produce at least one scaling factor in a range from greater-to-less than unity.
 15. In a material thickness gaging system, a signal conditioner for compensating an electronic material thickness signal for variations due to variations in material composition and temperature, said material composition and temperature represented by material composition and temperature signal sources, said signal conditioner comprising: a. first input means for receiving said electronic material thickness signal, b. second input means for receiving said material composition signal, c. third input means for receiving said material temperature signal, d. a first scaling amplifier receiving said electronic thickness signal and having gain adjusting means preset at a first scaling factor corresponding to the amount of thickness signal multiplication desired at a predetermined value of material composition, e. second and third scaling amplifiers each receiving said material composition-compensated thickness signal and each having gain-adjusting means preset at respective second and third scaling factors, said scaling factors corresponding to the amount of material composition-compensated thickness signal multiplication desired at lower and upper values of said material temperature, f. circuit means for proportioning the first and second amplifier output signals in response to said material temperature signal to produce a single composition and temperature compensated material thickness signal, and g. output means for issuing said composition and temperature compensated material thickness signal.
 16. Signal conditioner apparatus for compensating an electronic material gaging signal for variations due to variations in material second and third properties, said apparatus comprising: a. a material second property signal source, b. a material third property signal source, c. a signal conditioner comprising:
 17. Signal conditioner apparatus for compensating an electronic material gaging signal for variations due to variations in material second and third properties, said apparatus comprising: a. a material third property signal source, b. a signal conditioner comprising:
 18. The apparatus of claim 17 wherein said data source includes computer means for determining the presetting of at least one of said gain adjusting means.
 19. The apparatus of claim 17 wherein said data source includes computer means for controlling the setting of at least one of said gain adjusting means.
 20. The apparatus of claim 19 wherein said computer means is adapted to calculate a rate of change of said material third property signal and to enable the setting of at least one of said gain adjusting means to be regulated accordingly. 